(1) Field
The invention relates to a method for forming a mask pattern, and more particularly, to a method of forming a pattern on a mask sheet using a laser beam.
(2) Description of the Related Art
In order to manufacture a fine metal mask (hereinafter, referred to as a “mask sheet”) which is used for an organic light emitting diode (“OLED”) display, a chemical wet etching method is used. In this case, a stretching process which applies a counter force and a welding process are applied to the mask sheet which is manufactured by the wet etching method, and then the mask sheet is loaded on a mask frame. When the mask sheet is loaded on the mask frame, a method that stretches the mask sheet and welds the mask sheet to the mask frame is used in order to effectively prevent the mask sheet from being moved. In order to secure a final pattern position, the counter force needs to be applied.
However, the above-mentioned mask manufacturing method has a limitation in a manufacturing quality using the wet etching method due to a nano-sized pattern shape of the mask sheet due to a high resolution, e.g., 400 pixels per inch (ppi) or higher resolution, of the OLED display. Therefore, a mask manufacturing method that processes a pattern using a laser processing has been developed.
In the mask manufacturing process using a laser, instead of using a wet etching method, a mask sheet is manufactured using a laser beam. However, in order to fix the mask sheet to the mask frame, the same process which applies a counter force to the mask sheet and uses the complex stretching and welding process is used.